This invention relates to an improved device and manner whereby liners may be adhesively connected to the interior portions of container caps and the like and more particularly to a novel device for applying adhesive in a particular pattern and configuration upon the receiving surface of the cap prior to affixing a liner thereto.
It is common in the manufacture of container caps to provide the interior portions of such caps with a liner. Such liner may be formed from a wide variety of sheet materials including paper, cork and more recently plastic resinous compositions. Generally a preformed disc of such material is adhesively connected to the bottom of the cap to provide a finished appearance to the interior of the caps structure as well as in some case functionally serving to sealingly engage the top edge of the container on which the cap is adapted to be utilized.
Automatic equipment to accomplish the above described steps is available and generally includes a rotating table adapted to serially receive the unlined bottle caps, position them beneath an applicator station wherein glue or adhesive is is deposited on the inside surface and then to a liner inserting station wherein a liner is positioned in the cap and in contact with the adhesive. After maintaining the liner and adhesive in pressure contact with each other, if necessary, for the desired length of time, the caps are then removed from the table for subsequent use after inspection, packing and the like.
Applicators which spray, i.e. spurt, a quantity of adhesive in preselected patterns on the interior surface of caps, i.e. a receiving surface, are known. Such devices are adequate for many cap configurations especially relatively large caps and those which utilize relatively conventional liner materials which are easy to adhesively connect to the receiving surface thereof. There are, however, many cap configurations which incorporate a recess or core in the base of the cap in a position below the level of the threads so as to reduce the amount of plastic material used therein. Such coring reduces the ultimate material cost of the cap as well as desirably decreasing the molding cycle time thereof. With such cored cap constructions it would be wasteful to apply glue or adhesive in the central recessed areas as too much material would be required to fill the recess or well to insure contact with the liner disc. This is particularly true of hot melt adhesives which are expensive and particularly suited to adequately attach liner discs formed from many desirable pastic resinous materials such as the polyolefins.
It is therefore apparent that it would be desirable to apply the adhesive to the surface of the relatively flat ledge surrounding the recess of such cored caps. However, attempts to accomplish this as by the application of the previously mentioned technique has not met with complete success in that the adhesive tended to be directed upon the threads and was otherwise unsatisfactory.
It would accordingly be desirable to be able to apply semi-liquid material such as a hot melt adhesive on such a cap ledge surface in such a manner that liner discs including those formed from difficult to attach plastic resinous compositions may be satisfactorily adhesively connected thereto without the necessity of modifying presently available automatic cap lining equipment. It is accordingly a primary object of the present invention to provide a device for applying adhesive in a preselected pattern upon a cap receiving surface in a new and novel manner which eliminates the drawbacks of prior art devices.
A still further object of the present invention is the provision of a novel method of adhesively connecting liners to caps including liners formed from relatively difficult materials to adhesively attach thereto.
These and other objects of the present invention are accomplished by the provision of the device and the manner in which it may be utilized as hereinafter disclosed.